1. Field of the Invention
This invention relates generally to the placement of indicia on an interior surface of a container, and more particularly to apparatus for date-stamping the bottom surface of a portable fire extinguisher and similar vessels.
2. Description of the Prior Art
The National Fire Protection Association (NFPA) has set forth standards for portable hand held fire extinguishers classified as stored pressure types, which category includes both dry chemical and halon portable fire extinguishers, that requires such fire extinguishers be emptied and subjected to applicable maintenance procedures every six years. The standards specify that internal service tags be attached to a siphon tube of an extinguisher inspected as certification of such inspection. This manner of certification has been criticized as not assuring that the fire extinguisher has in fact been emptied and properly maintained prior to placement of the service tag.
U.S. Pat. No. 2,963,961, issued Dec. 13, 1960 to J. F. Sundstrom discloses a method for date-stamping a soft plug provided in the bottom of a mold by inserting a punch provided with a marking element at a tip thereof into an entranceway of a mold to be stamped and causing the marking element to imprint the soft plug. A problem with this technique, however, is that a special container must be constructed provided with a soft plug in the bottom thereof, and with a special collar arranged around an entranceway into the vessel in order to receive the marking tool.
U.S. Pat. No. 4,667,594, issued May 26, 1987 to A. W. Addy discloses an imprinting apparatus in which an expansible block expands to print on interior side walls of a hollow article such as a tape-roll core. A problem with this technique, however, if applied to the marking of containers, is that imprints on an interior side wall of a vessel are not always visible to one looking into the vessel through an access opening provided in it.
U.S. Pat. No. 1,590,905, issued Jun. 29, 1926 to J. J. Rettmer, and U.S. Pat. No. 4,401,030, issued Aug. 30, 1983 to J. E. Connolly et al, disclose examples of portable marking tools using a reciprocating movement of a marking member in order to make a mark. These devices, however, are not suitable for use with standard containers such as fire extinguisher bottles.
U.S. Pat. Nos. 2,771,026, issued Nov. 20, 1956 to L. P. Mooney, 2,778,306, issued Jan. 22, 1957 to C. C. Harris, 3,333,536, issued Aug. 1, 1967 to W. P. Messersmith and 3,948,173, issued Apr. 6, 1976 to K. S. Barasch, disclose inking devices in which an inked pad is disposed in a cup-like receptacle so as to be engaged by a rubber or similar stamping element and be in an inked condition when needed to perform a printing operation.